As a real user of X100, Xpro-1 and Nex-7, I can assure you that the EVFs of any of these cameras are really dim in bright light.

The back illumination LEDs of the EVF simply cannot compete with the sunlight when your eyes are adapted to bright daylight. Having said that, EVFs are, of course, far from being useless. You can still compose and read the settings; they are just harder to see in bright light. On the flip side, they look great in dim light.